Is it possible to transport materials between the Internal render and Cycles render for animation?
Materials for blender internal have limited support for nodes, while cycles uses nodes only. The cycles nodes will not work for internal materials nor will internal nodes or material settings work with cycles.

You can create a material that has both nodes in it. There are some nodes that are common to both and can be interlinked with each other.

What this means is you cannot use the same nodes for both render engines, but you can integrate two node setups into one material so that one material can be used for both render engines.

For a simple material that uses an image texture and a diffuse node this will be a simple task. For more complex materials you may find it hard to get the two to match up.

As an example you could look at the materials used in CGCookies Flexrig, the materials there are deliberately created to work with both render engines.

While not large enough to be very clear this is one of the materials in the Flexrig, The red and green frames are cycles nodes while the darker section at the bottom is for BI. The purple section is common values used in both node setups. The cycles nodes appears simpler because they are groups.